Among various flat-panel displays, the liquid-crystal display (LCD) has become the mainstream in the market because of its superior characteristics, such as light weight, low power consumption, no radiation, and full color image. As technologies used in optoelectronics and semiconductors have advanced, liquid-crystal displays with high resolution, rapid response time and high image quality have flourished accordingly. For example, active matrix liquid-crystal displays with thin-film transistors are generally substituted for passive matrix liquid-crystal displays (such as twisted nematic (TN) LCD, super twisted nematic (STN) LCD, or bistable twisted nematic (BTN) LCD). To fulfill the demand for wide viewing technology, the development of wide viewing LCD such as in-plane switching (IPS) LCD, fringe field switching (FFS) LCD, vertical alignment (VA), and polymer sustained alignment (PSA) is quite important.
In order to enhance the characteristics of a liquid-crystal display device, a liquid-crystal composition used by the device may be equipped with suitable properties, such as high dielectric anisotropy (Δε), low rotational viscosity (γ1), and suitable birefringence. Specifically, a liquid-crystal composition with high dielectric anisotropy facilitates the reduction of the threshold voltage (Vth) of the liquid-crystal device employing the same; a liquid-crystal composition with a low rotational viscosity has a fast response time; and a liquid-crystal composition with a high clearing point exhibits a broad operating temperature range.